Effect of Out-Of-Hour Admission on Fluid Treatment of Emergency Department Patients with Suspected Infection; a Multicenter Post-Hoc Analysis.

Introduction: Sepsis is a life-threatening and common cause of Emergency department (ED) referrals. Out-of-hour staffing is limited in ED, which may potentially affect fluid administration. This study aimed to investigate fluid volume variation in out-of-hour vs. routine-hour admissions.

Methods: The present study is a post-hoc analysis of a multicentre, prospective, observational study investigating fluid administration in ED patients with suspected infection, from Jan 20^th - March 2^nd, 2020. Patient groups were "routine-hours" (RH): weekdays 07:00-18:59 or "out-of-hours" (OOH): weekdays 19:00-06:59 or Friday 19:00-Monday 06:59. Primary outcome was 24-hour total fluid volumes (oral + intravenous (IV)). Secondary outcomes were total fluids 0-6 hours, oral fluids 0-6 and 0-24 hours, and IV fluids 0-6 and 0-24 hours. Linear regression adjusted for site and illness severity was used.

Results: 734 patients had suspected infection; 449 were admitted during RH and 287 during OOH. Mean (95% CI) total 24-hour fluid volumes were equal in simple infection and sepsis regardless of admission time: Simple infection RH: 3640 (3410 - 3871) ml and OOH: 3681 (3451 - 3913) ml. Sepsis RH: 3671 (3443;3898) ml and OOH: 3896 (3542;4250) ml. Oral fluids 0-6h were reduced in simple infection and sepsis among OOH vs. RH. Sepsis patients received more 0-6-hour IV fluid when admitted OOH vs. RH. There were no associations between admission time and 0-24-hour oral or IV volumes in simple infection or sepsis.

Conclusion: Admission time did not have an association with 24-hour total fluid volumes. Sepsis patients admitted during OOH received more 0-6-hour IV fluids than RH patients, and simple infection and sepsis patients received less oral fluid in 0-6 hours if admitted during OOH vs. RH.